My 18is is consuming way to much fuel...

[MVincken]

the power of the engine is ok it seems, but i didn't check by any means. How do i go about checking that?

only waz to be sure the engine produces the power is a dyno, hiring a dyno isn´t cheap so probably not the best first option.
better go to a workshop and let them check your cilinder compression.

[MTD]

only waz to be sure the engine produces the power is a dyno, hiring a dyno isn´t cheap so probably not the best first option.
better go to a workshop and let them check your cilinder compression.

Thanks, the car is going to the mechanic this week, I'm going to ask him to check it out

[gespinal0301]

Any update?

[MTD]

Any update?

Sorry no updates. Didn't go to the mechanic, some busy weeks right now, exams...
One thing i did discover, on one of the tanks i filled recently i decided to "not care" and just drive harder than usual. Not racecar like, but not caring about being below 3000rpm and etc. The difference in fuel consumption was not much by surprise. From 10,2 l/100 to 11,3l/100

[MVincken]

that "new driving" principle doesn´t work on our beloved m42´s tho.. if i have to drive like they say what´s best for MPG etc i have to shift around 2500rpm.
for cruising this is sort of correct, but when you´re driving on normal roads it´s better to keep off the pedal below 2000rpm, flooring it in the low rpm range will demand way to much from our revvy and torque-less engines. this can blow you milage too.

but still i think you have a bigger problem, best to check the exhaust gasses on amount of oxigen. lambda failure or something else can make you car run way to rich. this is a sort of failsafe made by bmw, better to drive an engine rich than lean in unknown conditions.

[MTD]

that "new driving" principle doesn´t work on our beloved m42´s tho.. if i have to drive like they say what´s best for MPG etc i have to shift around 2500rpm.
for cruising this is sort of correct, but when you´re driving on normal roads it´s better to keep off the pedal below 2000rpm, flooring it in the low rpm range will demand way to much from our revvy and torque-less engines. this can blow you milage too.

but still i think you have a bigger problem, best to check the exhaust gasses on amount of oxigen. lambda failure or something else can make you car run way to rich. this is a sort of failsafe made by bmw, better to drive an engine rich than lean in unknown conditions.

Yeah true!
Well the car is most likely going to the mechanic soon, some new parts also arrived (suspension arm or something like that, i can't say it in english lol)

[MTD]

Hey guys. I have another "symptom" that might give some clues on this problem.
Lately the car is having some problems starting up. Sometimes ill turn the ignition, electrical part all on, i turn the key... and nothing. I have to turn the electrics off and do it again. Sometimes 2 or 3 times. Once it starts cranking (i don't know if this is the right term sorry - english is not my 1st language) it always goes all the way and starts the car, but the problem is those times it doesn't even start "cranking".

Does this give any insight on the fuel economy issue?

[Lmg]

Hey guys, my 18is is consuming way too much, I do not know what's going on ... Lately I will always get 11 l/100 (Or 21.5mpg for the US folks). For the type of driving I do, and the engine that it is, it's way too much. 70% of my driving is in the freeway, in 5th gear at 2200/2500rpm. little traffic. Shifting at 3000rpm. Etcetc. I may do 1 or 2 agressive starts each tank of fuel, but thats it.

Given my type of driving, i should be getting much less fuel comsumption. I have no idea what it may be, since the car was revised and changed filters 1 month ago. Do you think?

check your alignment. I just put in an e46 rack and drove on it for about 100 miles of mixed city/highway. went from 29mpg down to 20mpg. Car felt wayyy better after having it aligned and mpg has gone up.

[Lmg]

I'm averaging 27 actual mpg, that's 60% highway and 40% local. What does your coolant gauge read, could it be an open thermostat causing the engine to think it's cold?????

+1

Does your heater blow hot air or simply warm air?

[MTD]

check your alignment. I just put in an e46 rack and drove on it for about 100 miles of mixed city/highway. went from 29mpg down to 20mpg. Car felt wayyy better after having it aligned and mpg has gone up.

Alignment is not the problem, i got it aligned about a month ago. Will also do it again in 2 weeks when i get the new wheels. What i do have is a slightly loose "suspension triangle" (i don't know how to say it in english right, but it's this part: http://i.ebayimg.com/00/s/NDU4WDQ1OA==/z/lh4AAOSwMmBViAI5/$_35.JPG)
But that will be taken care of next week as well, i already have the new parts with me. I suppose that shouldn't be the source of the fuel consumption right?

+1

Does your heater blow hot air or simply warm air?

It blows hot air

[mjimport]

^ that's a control arm, very important component to hold your alignment. In my opinion you should not have had an alignment done with a worn out control arm bushing/ball joint.
With that said, it could also impact mpg.

[MTD]

^ that's a control arm, very important component to hold your alignment. In my opinion you should not have had an alignment done with a worn out control arm bushing/ball joint.
With that said, it could also impact mpg.

When i got it aligned i did not know i had a problem in the control arm. Well,lets hope that it improves my mpgs when i put in the new ones *fingers crossed*

[mjimport]

Hope it works out for you. I would think you would notice some pretty nasty shaking if they were worn enough to cause much mpg loss.

[MTD]

Hope it works out for you. I would think you would notice some pretty nasty shaking if they were worn enough to cause much mpg loss.

Yeah it does shake. I don't know what is considered "nasty", but at high speed turns and bumps i can hear it rattling. If i drive "normally" it doesn't rattle

[MTD]

Hey guys, so the car is finally back from the mechanic today. It was currently doing 12.2l/100 (before mechanic). Things that were done:
-New control arms
-New bushings
-New wheel bearing for front left wheel
-Lambda sensor got cleaned up and fixed, wasn't working properly
-other sensors all around were "touched up" and overall priming of car

Things he noticed that will need fixing:
Somewhat urgent: front right shock, almost gone
Not so urgent : the catalyzer is getting a bit obstructed, not much right now but still

Also right now the alignment is fucked up, given the work he did.

So... Let's hope the fuel consumption drops! Filled a tank today, will report when I have results!